基质金属蛋白酶与心血管疾病及其法医学意义

在心血管疾病发病机制中起重要作用的蛋白质大分子,对于心脏性猝死的发生及确诊具有十分重要的意义。基质金属蛋白酶(Matrixmetalloproteinases,MMPs)是一类锌依赖的金属内肽酶的总称,是降解心肌细胞外基质最重要的蛋白水解酶类。本文就基质金属蛋白酶生物学特性、功能在心血管疾病发生发展中的作用和在法医病理学中的意义作一介绍。     

刑事照相全过程数码化

当今,我国各地公安机关刑事技术部门都已经逐步实现了刑事照相全过程数码化。数码相机的优点使得其被广泛运用于刑事案件的现场照相、物证照相和辨认照相中,而数码案件照片则可利用Photoshop等图像处理软件来对其进行后期的编排和处理,亦可巧用Photoshop软件,轻松地将数码痕迹图像处理为所需用比例物证检验照片。将数码照相技术与指纹自动识别系统相连接,使数码指纹照片直接进入指纹自动识别系统中进行校验比对,“锁定”作案者指纹。     

利用尸体角膜内皮细胞活性率判定死后经过时间的研究

本研究对已知死亡时间的500只非正常死亡者的角膜内皮细胞进行染色观察，以单位面积内的活性内皮细胞与细胞总数之比作为活性率，发现角膜内皮细胞活性率（Endothelialcelllivinsrate，ECLR）随死后经过时间（postmorteminterval，PMI）的延长而逐渐降低，数理分析表明两者之间的关系为负相关，因此，认为检测尸体角膜内皮细胞活性的方法可为法医学推断死后经过时间提供一新的组织学手段。     

Post-mortem interval estimation using miRNAs of road traffic accident cases: A forensic molecular approach

In forensic examination accurate estimation of post-mortem interval (PMI) is a challenging task, particularly in the advanced stages of decomposition. The existing methods (algor mortis, livor mortis, rigor mortis, putrefaction etc) used for estimating PMI rely on analyzing the physical, biochemical, and metabolic changes that occur in the corpse after death. While these methods have shown some level of effectiveness in estimating PMI during the early stages of decomposition, accurate estimation becomes increasingly challenging during the later stages of putrefaction when the body undergoes significant changes. Recently, microRNA (miRNA) profiling due to its relatively small size and stability has emerged as a promising tool in several areas of forensics. This study demonstrates the potential of miRNA for PMI estimation in advanced stages of death. In this study, miRNA-195, miRNA-206, and miRNA-378 were selected as target miRNAs and miRNA-1 as reference miRNA. Left ventricle tissue (5 g) of the heart from 20 forensic autopsies of traffic accident victims (18–32 years) were collected and processed. The samples were held at room temperature for eight different time intervals (12, 24, 48, 72, 96, 120, 168 and 196 h), and RNA was extracted from all the samples using Trizol-based RNA isolation protocol, followed by cDNA synthesis and amplification with commercially available specific miRNA probes in Real-Time PCR (RT-PCR), Ct was calculated. The result showed that miRNAs were associated with PMI. Over time, there were substantial changes in the Ct values of all three miRNAs, with significant reductions observed at 196 h compared to 12 h. miRNA-206 demonstrated significant changes at multiple time intervals, while miRNA-1 remained stable for up to 196 h and thus holds caas an endogenous marker. In conclusion, miRNA has the potential to serve as a valuable tool for estimating PMI, especially during the advanced stages of decomposition, when used in conjunction with established techniques. However, further validation of the study is required to obtain more accurate estimates of PMI.     

Novices cannot fill the examiners’ shoes: Evidence of footwear examiners’ expertise in shoe comparisons

The value of a footwear examiner’s opinion centres on their ability to determine whether a particular shoe made an impression with greater accuracy than a novice. However, there has been limited research on the expertise of footwear examiners and the accuracy and reproducibility of their decisions. In the current study, we measured the accuracy and consensus of 31 footwear examiners versus a comparison group of 29 novices. Participants completed 20 ground truth known mock shoe comparisons. Results demonstrated that footwear examiners were more accurate than novices, regardless of comparison difficulty. Overall, on trials where probative decisions were given, examiners made false identifications and false exclusions on a total of 3% and 2% of trials, while novices made false identifications and false exclusions on a total of 19% and 17% of trials. Examiners also demonstrated better consensus in their opinions than novices, although both groups demonstrated low levels of agreement in their responses and variability in their interpretation of the conclusion scale. In summary, these findings support the proposition that footwear examiners show expert-level performance in matching known and unknown footwear impressions. These performance estimates may help the criminal justice system to appropriately value footwear examination evidence.     

Ghosting phenomenon in static and dynamic footprints in India and the United States

Ghosting is the phenomenon that exists when a footprint has a lighter area around the tip of one or more toes or a shadow-like area at the back of the heel. To date, ghosting has been considered primarily a finding of dynamic (walking) footprints, rather than static (standing) footprints. The prevalence of ghosting in static footprints is unknown, and research on its presence in static and dynamic footprints from the same participant is sparse, as are studies on its occurrence in different geographic populations. This study is among the first to evaluate the occurrence of ghosting in the static and dynamic footprints from a particular individual with participants in two geographic populations.A combination of both inkless and ink footprint collection systems were used to obtain a total of 206 bare footprints from 103 adult participants from the United States and India. The data comprised 103 static and 103 dynamic footprints.Ghosting occurred significantly in static footprints, though less frequently than in dynamic footprints. Ghosting in static footprints was seen most often at the first toe, followed by the third and second respectively. This aspect appeared least at the heel. In dynamic footprints, it occurred most at the first toe, followed by the second and fourth toes, and then the third toe and the heel. The prevalence of ghosting in footprints from the United States and India differed in their locations, notably at the first and second toes in the static footprints and at the heel in the dynamic footprints.     

Footwear-to-feet examination and analysis: Comparing worn footwear to persons and human remains

Footwear-to-feet examination and analysis refers to the process of examining and analyzing footwear in regard to criminal matters. This examination and analysis has been done to include or exclude an individual as the wearer of the footwear in question and to help associate or disassociate human remains to footwear. This review of the subject describes its investigative applications, the research that underpins the process, and considers its legal admissibility. The process of footwear-to-feet examination and analysis is scientifically valid and has been widely accepted. As a result, law enforcement and forensic scientists should be aware of the use of this process to assist in criminal investigations.     

The contact area of static and dynamic footprints: Forensic implications

When found at crime scenes, footprints may be evidentially valuable and can assist with the identity of a perpetrator based on their features and/or measurements. Footprints can be either static (made while standing) or dynamic (made while walking). While extensive research has been performed on the linear measurements obtained from static and dynamic footprints, research on the comparisons between the contact area of static and dynamic footprints in the forensic context are limited. The present study compares the contact area of static and dynamic bare footprints to determine if statistically significant differences exist between the two. Static and dynamic footprints were obtained from a sample of randomly-selected 461 Jatt Sikh adults (230 males and 231 females) of Indian origin between the ages of 19 and 32 years. The footprint contact area was calculated from each footprint (excluding the toes) using a PedoGRID® sheet. No statistically significant differences were observed between the contact area of static and dynamic footprints for each foot among males and females. However, statistically significant differences between both the sexes were found in the footprint contact areas of both footprint types. The right dynamic footprint contact area was found to be the most predictive measurement for classifying and estimating sex from a footprint’s contact area. The study has implications in the analysis of footprints recovered from crime scenes.     

Recovery of single source DNA profiles from mixtures by direct single cell subsampling and simplified micromanipulation

Deconvolution of forensic DNA mixtures into their individual component DNA (geno)types is of great investigative value, though often complex and difficult. Two-person mixtures comprising a major and minor contributor are often easily interpreted although, when the DNA ratio of the two individuals is approximately equal (~1:1), deconvolution and interpretation becomes much more difficult. To address this issue, a physical separation of individual-, two- or three- cell subsamples prior to autosomal STR analysis was performed using a simplified micromanipulation technique paired with a decreased reaction volume and increased cycle number PCR. Using this method, single and multiple buccal epithelial cells were collected from a 1:1 two-person mixture (i.e. from individual 'A' and 'B') and directly amplified, omitting standard DNA extraction and purification steps. Single cell subsamples resulted in partial single-source profiles for both contributors while, in accordance with expectations of a quasi-binomial sampling schema, two- and three-cell subsamples resulted in single source informative partial profiles of individual A and individual B as well as complete consensus profiles, and equally mixed 1:1 (2-cell subsamples) and 2:1 (3-cell subsamples) admixed profiles of individual A and B. This proof-of-concept approach shows promise in permitting the DNA deconvolution of mixed samples where the individual contributors are present in similar amounts that would otherwise be difficult to interpret, resulting in an increase in evidentiary value. The subsampling approach can be readily investigated for DNA casework applications without additional investment in costly, new equipment, requiring only a stereo microscope and a tungsten needle.